Device for measuring fiber density of a sliver



March 29, 1949. j; L. RICHARDSQN 2,465,818

DEVICE FOR MEASURING FIBER DENSITY OF A SLIVER Original Filed June 26. 1943 Inventor:

Ernest L ,.Rchardson,

,by His Attorney.

Patented Mar'. 29, 1949v DEVICE FOR MEASURING FIBER DENSITY F A SLIVER f Ernest L. Richardson, Melrose, Mass., asslgnor to General Electric ACompany, a corporation of New York Original application June 26, 1943, Serial No.

492,425. Divided and this application December 13, 1945, Serial No. 634,793

3 Claims.

This invention relates to'measuring devices, more particularly to devices for measuring the fiber density yof an array of bers such as a sliver; and it has for an object the provision of a simple, reliable, inexpensive and improved device of this character.

This application is a division of application Serial No. 492,425, filed June 26, 1943, now Patent 2,407,100, and assigned to the same assignee.

In certain of the preparatory steps in the processing of fibers to form a yarn or thread, a length of material such as a sliver or roving, containing an array of bers, is subjected to a series of drafting operations before being converted into the final yarn or thread form.

When the material is made up in the sliver form for the first time, whether it be by means of carding or in any other manner, it falls far short of the ideal insofar as regularity and unif ormity of density are concerned. The constituent bers are by'no means perfectly mixed, and both long and short wave variations in thickness are considerable.

Another object of the invention is the provision of means'for detecting variations in the density of the bers of the sliver, and for providing an indication'of the magnitude of such variations.

In carrying the invention into effect in one form thereof, a fluid such as air is caused to ow through the fibers of a length of material such as a sliver of which the fiber density is to be determined. The resistance to the flow of air offered by the array of fibers constituting the sliver is a measure of the fiber density, and thus by measuring variations in resistance to the flow of air through the ber array the amount of variation from uniformity can be determined.l`

One form of a device for measuring the resistance to flow of air through the fibers comprises a member provided with a passageway through which the length of material passes. This member is recessed to provide a. chamber in communicatlon with the passageway. Air from a suitable source of constant pressure is supplied through a restricted orice to this passageway and escapes in opposite direction through the fibers. The air pressure in the chamber is a measure of the ber density of the array of bers passing through the passageway.

In a modied form of the invention, the detector, i. e. the member containing the passageway, is provided with a plurality of chambers which are in fluid communication with the passageway.

For a better and more complete understanding of the invention, reference should now be had to the following speciiication and to the accoml panying drawing of which Fig. 1 is a simple, diagrammatic sketch of the embodiment of the invention, and Fig. 2 is a sectional view of a modified form of a detail.

Referring now to the drawing, a'sliver I containing an array of loose fibers is illustrated as being passed in the direction of the arrow 2 through the nip of a pair of rollers 3 to a subsequent stage in the process. The rollers 3 may be driven by any suitable driving means (not shown).

For the purpose of detecting variations in the ber density of the sliver, a flow tube device l is provided. Although the flow tube detecting device 4 may be made in any suitable manner, it is illustrated as comprising a pipe T member 4a which is provided with an insert 4b. The insert member is tapered from both ends toward the center to provide a flow tube passageway for the passage of the sliver l, and is recessed approximately midway between the enteringand delivery ends of the tube to provide a chamber 4c in communcation with the passageway through which the sliver I passes.

A fluid such as air is supplied from a suitable source, such as the mill supply, through a re-l 'ber 4c through the orce 5 is maintained substantially constant by means of a pressure regulating device 6, which is included in the pipe connections between the source and the orifice 5. This pressure regulator comprises a bleed valve 6a which is loaded by means of a-spring 6b. 'I'he bleed valve 6a. is fastened to one end of a lever 6c, of which the opposite end is provided with a knife edge which rests in the bottom of a V-shaped slot in a block 6d to provide for pivotal movement of the lever. One end of the loading spring 6b is secured to a stationary part such, for example. as the` pipe 'I and the other end is attached to a screw 6e which passes through the lever 6c and is provided with a nut 6f for adjusting the tension of the spring to provide the desired loading of the valve. The valve 6a has a' maximum movement of approximately .003 inch so that the change in spring gradient is negligible.

With variable inlet air pressure from the supply source through the throttling valve 8 the spring loading is adjusted for the desired pressure and the throttling valve is adjusted to give a. small opening of the bleed valve corresponding to the minimum inlet pressure. With increase in the inlet pressure the bleed valve opens a very small amount to dispose of the increased flow passed by the throttling valve and thereby maintains a substantial constant pressure to the orifice 5. The restricted orifice 5 is preferably mounted in one arm of a pipe elbow 9.

A pressure responsive indicating device, such as a Bourdon gauge I 0, is connected to the vertical pipe II leading to the pressure chamber 4c -for the purpose of providing a visual indication of the pressure in the chamber 4c and the density of the fibers of the sliver I passing through the passageway of the ow tube detecting device.

In operation, air passes through the restricted orice 5 to the chamber 4c. -From the chamber air passes in opposite directions through the .spaces between the fibers through the entering and delivery inserts of the flow tube. The rate of flow of air from the chamber 4c will remain constant as long as the density of the sliver flowing through the flow tube detecting device remains constant at the desired value.

However, if a relatively thicker portion of thel sliver approaches the detecting device, the density of the fibers entering the passageway of the flow tube tends to increase. As a result 'of this tendency of the ber density to increase, the flow of air from the chamber 4c through the flbers in both directionsA will be correspondingly restricted and this will cause the pressure in the chamber 4c to increase. When the fiber density of the sliver returns to the predetermined desired value, the pressure in the chamber 4c returns to the normal value.

If a portion of the sliver which is relatively thinner than the normal value approaches the flow tube detecting device, the density of the bers entering the passageway tends to decrease ,so that the fibers willoier less resistance to the flow of air from the chamber 4c to atmosphere. This will cause the pressure in the chamber 4c to decrease.

In Calibrating the dial of the Bourdon tube indicating device I0, it is feasible to use the total 'fiber cross-section of the sliver as a measure of density. When density is soA considered, the calibration is identical'for all types of fiber, except for insignificant differences owing to the variation in the air flow coefficient caused byA variation in fiber surface friction. The density of a given type of benis also frequently measured in terms of weight in grains per yard and a different calibration for each type of material is required on account of the varying specific gravities of fibers of different materials.

The ow tube detecting device may take the form illustrated in Fig. 2. As shown in Fig, 2, the flow tube detecting devicel I2 differs from the detecting device 4 of Fig. 1 in that the sizes of the sliver ow passages in the inserts I2a and 12b in the entering and delivery ends of the tube are different and also in the provision of a plurality of internal barriers I 2c and I2d which are substantially equally spaced between the ends to provide a plurality of air chambers I2e, I2f and |29. The barriers I2c and I2d are provided with centrally disposed passages which are graduated in size such that when centrally aligned with the passages in the inserts I2a and I2b there is provided for the sliver I a passageway of which the size decreases uniformly from the entering to the discharge end. The end inserts I2a and I 2b and the internal barriers I 2c and I2d may be made vof steel and their surfaces which constitute the passageway for the sliver may be chromium-plated to minimize resistance to the flow of the silver.

Air is supplied to the chambers I2e, I2f and I 2g from a manifold I3 which in turn is connected by means of a pipe I4 to the source of regulated air supply, i. e. to the pipe II of Fig. 1.

Although in accordance with the provisions of the patent statutes this invention is described in concrete form and the principle thereof is ex plained together withthe best mode in which it is now contemplated applying that principle, it will be understood that the elements shown and described are merely illustrative and that the invention is not limited thereto since alterations and modications will readily suggest themselves to persons skilled in the art without departing from the true spirit of this invention or. from the scope of the annexed claims.

What I claim as new and desire to secure by Letters Patent of the United States, is:

1. In combination, a tubular member provided with a passageway for a moving length of material containing an array of fibers and having an annular centrally disposed chamber in communication with said passageway, said passageway tapering from a relatively large opening at each end of said tubular member to a relatively small opening at the point of communication with said chamber, a source of substantially constant uid pressure for supplying fluid to said chamber and forcing fluid from said chamber through said fibers, thereby to produce variations in the fluid pressure in said chamber in response to variations in the density of said length of material, and means responsive to the fluid pressure in said chamber for indicating the density of said material.

2. In combination, a tubular member provided with a restricted passageway for a moving length of material containing an array of bers and having an annular centrally disposed chamber communicating with said passageway, said passageway tapering from a relatively large opening at each end of said tubular member to a relatively small opening at the point of communication with said chamber, an orifice,- a substantially,

constant source of fluid pressure for supplying fluid through said orifice to said chamber'and y forcing fluid from said chamber through said fibers thereby to produce variations in the uid pressure drop across said orifice in response to variations in the density of said fibers, and means responsive to the fluid pressure in said chamber for indicating the density of said material.

3. In combination, a tubular member provided with a passageway for a length of material containing an array of fibers recessed between the inlet and outlet of said passageway to form a compartmented chamber surrounding said passageway and in communicationv therewith, said passageway tapering from a relatively large opening at each end to a relatively small opening at the point of communication with said chamber, a source' of substantially constant fluid @essere y pressure for supplying iiuid to said chamber and v l forcing fluid from said chamber through said Y i Y REFERENCES CITED bers and out through said inlet and outlet y The following references are o f record in the thereby to produce variations in fluid pressure in me 0f this patent: said chamber in response to variations in density 5 UNITED of the fibers of said length of material, and means STATES PATENTS responsive to the iiuid pressure in said chamber Number N Bme Date for indicating the density ot said material. 1,599,964 Haven Sept. 14, 1928 f 2,014,998 Baguley et al. Sept. 17, 1935 ERNEST L. RICHARDSON. l0 2,077,525 Mennesson Apr. 20, 1937 2,276,036 Hanna et al, Mar. 10, 1942 2,348,985 Lewis May 16, 1944 

